1. Field of the Invention
The present invention relates generally to apparatus for orienting a plurality of objects and, more particularly, to a sorting and orienting apparatus for closures for containers.
2. Background Information
Closures for containers, such as, for example, bottle caps and jar lids typically have an asymmetrical shape with a top or flat surface having sides protruding from the underside thereof to form a shallow cup-like shape.
Before such closures are used, for example, during automated bottling or food packaging processes, the closures must be accurately sorted and oriented. A variety of automated sorting machine designs have been employed in an attempt to sort and orient closures in the most efficient manner possible. Efficient sorting requires proper orientation and transport of the maximum number of closures possible while effectively sorting to remove incorrectly arranged closures and simultaneously preventing jamming as the correctly oriented closures are delivered, and performing all of these functions throughout the entire duration of a particular sorting run.
Known prior art sorting machines use a variety of mechanisms and techniques to correctly orient closures while sorting out incorrectly oriented closures (i.e., closures that are improperly arranged in the sorting area, such as, for example, overlapping, upside down or otherwise incorrectly situated closures).
A few of these sorting machines include a large hopper for holding a quantity of closures and distributing them onto a conveyor belt, and utilize gravity and the geometry of the closures to facilitate sorting. Maintaining proper depth of the closures during loading onto the conveyor belt is critical to optimize sorter efficiency. Known prior art hopper designs exhibit a large variation in performance efficiency as the hopper diminishes its load of closures during the sorting run, from when the hopper is full of closures to the end of the sorting run when the hopper is nearly empty.
Adjusting the sorter to sort a different closure type or size often requires a different conveyer flight design. Flights are projections or the sections of the conveyor belt structured to retain a closure in the proper orientation. A conveyer flight is dimensioned based on specific closure properties. Existing methods of changing the flights are very time consuming, requiring the use of tools and involving a lot of effort. Additionally, existing belt-type sorter designs maintain an inclined belt path, causing the size of the sorter footprint, or base dimension, to expand as the path is extended to accommodate different closure shapes and sizes. This also requires support structure well beyond the boundaries of the base or footprint of the machine, thereby unnecessarily occupying extra floor space or work area.
Once closures near the top of the sorter conveyor belt path they must be removed from the conveyor belt. Known methods of closure removal include, for example, sweeper bars and high-pressure compressed-airjets. However, sweeper bar methods can be slow and are prone to jamming and compressed air is very loud, inefficient and poses contamination issues. Other designs use an adjustable disruption in the belt path to dislodge improperly oriented caps. However, such a feature typically involves numerous bearings and other moving parts, as well as tedious adjustment mechanisms.
Improperly oriented closures often fall off the flights as they are carried on the conveyor belt to the discharge area at the top of the sorting machine. Falling closures can knock properly oriented closures off the conveyor belt near the loading area thus reducing the overall efficiency of the sorter. Many sorters have overflow paths that allow closures to drop down a chute and back into the bulk hopper. Typically, such overflow paths comprise a long corrugated hose. Such hoses are difficult to clean and inspect. Additionally, allowing closures to make multiple passes through the sorter increases the chance of damage and/or contamination of the closures.
U.S. Pat. No. 5,394,972 (Aidlin et al.) discloses a variable angle conveyer assembly. The patent recites a conveying system for lifting and orienting bottle caps comprising a conveyor belt which is formed with articulating sections. The belt has an upper lifting section with an essentially vertical path of travel and a lower loading section with an angled path of travel. The assembly includes a complex swing-arm arrangement to displace the belt path. The swing-arm includes a shaft having ball-bearings to facilitate rotation and a plurality of sprockets in contact with the interior face of the conveyor belt near the bottom of the upper section, in order to form an outwardly directed bow in the belt. The bow facilitates removal, by gravity, of bottle caps not in the proper orientation on the conveyer belt. Adjustment of this mechanism requires the use of tools, such as, for example, a wrench. The bottle caps are initially disposed in a hopper located proximate the loading section of the conveyer belt. At the bottom of the hopper is a baffle plate with holes on the sides to permit caps to be loaded onto the conveyer belt while the center of the baffle plate supports the pressure of the caps in the hopper. However, this hopper design results in a variation of the level of caps dispensed to the loading section corresponding to variations in the fill-level (i.e., the number of caps in the hopper). Accordingly, optimal sorter performance cannot be maintained throughout the full operating range as the hopper fill-level diminishes. The assembly also includes a pressurized fluid source such as compressed-air to pneumatically eject bottle caps from the conveyer belt.
There is room for improvement in the art of object sorting and orienting and in closure sorting and orienting apparatus.